Laser Methane Detector

The laser CH4 detector (LMD) is a highly responsive, hand-held device that is pointed at an animal’s nostrils and measures CH4 column density along the length of the laser beam (ppm.m). In the first implementation of LMD on a farm, measurements for each cow were taken over periods of 15 to 25 seconds between eructation events and could detect CH4 emitted each time the animal breathed out (Chagunda et al., 2009 Sorg et al., 2016, 2017). In a later study with sheep and beef cattle, monitoring periods of 2 to 4 minutes allowed authors to separate breathing cycles from eructation events (Ricci et al., 2014). Typically, animals are restrained either manually or in head yokes at a feed fence for the required length of time. The operator has to stand at the same distance (1 to 3 m) from each animal every time and must be careful to keep the laser pointed at the animal’s nostrils throughout the measurement period.